Field
The present specification generally relates to laminated sealing sheets and more specifically to a laminated sealing sheets used in glass-to-glass sealing to form hermetically sealed glass packages.
Technical Background
Hermetic glass-to-glass seals may be used in many industries, such as, display technologies, semiconductor technologies, lighting technologies, and photovoltaic technologies. Historically, some hermetic glass-to-glass sealing processes utilized elevated temperatures during the sealing process, which can lead to damage of the resultant sealed product. For example, in sealing organic light emitting devices/diodes (OLEDs), sealing processes that transfer excessive heat to the active organic layer can damage the active organic layer. In addition, OLEDs can be susceptible to environmental degradation from exposure to water vapor, oxygen, or both, which can be deleterious to the organic material and the electrical components of the OLED structure.
To minimize excessive heat transfer and environmental contaminations, laser-fit sealing, laser direct-glass sealing, and thin-film low-melting glass sealing have been employed. Laser frit sealing can add the cost of having to pattern the frit line before applying the laser or of having to apply a layer of frit to the sheet. Direct-glass-sealing can suffer from the disadvantages of poor optical transmission through the sealing sheet and the high cost of making exotic (expensive) laser-absorbing glass. The thin-film low-melting glass sealing involves a thin film sealing layer that is typically from about 0.5 to about 2.0 microns in thickness being applied to an exterior glass carrier surface. Therefore, the thin film material is not fusion formable and is supplied by sputter coating onto the glass carrier, which can add cost to sputter coat the material onto glass, especially since sputtering is an inherently slow process and large vacuum equipment may be required. In addition, the thin film sealing can be subject to damage, such as scratching or delamination. Glass-to-glass sealing may also be done with polymeric or filled polymeric materials, but these seals may not provide the degree of hermeticity needed for certain applications. Glass seals can also be created by anodic bonding, but this can require high voltages, which would not be suitable for applications having electronic circuits already patterned on the glass.
Alternative approaches for glass-to-glass sealing are disclosed herein.